This application is based on Application No. 2000-156697, filed in Japan on May 26, 2000, the contents of which are hereby incorporated by reference.
This invention relates to a vacuum circuit interrupter and, more particularly, to a vacuum circuit interrupter for use in a switchgear for a three-phase ac circuit provided with a device for interrupting the power system upon the generation of a fault in the power system for example.
In a conventional switchgear for a three-phase ac circuit, as shown in FIG. 3, three vacuum valves 3, 4 and 5 constituting a vacuum circuit interrupter 2 are disposed within a hermetic vessel 1 filled with an electrically insulating gas, with their axes arranged in parallel and side-by-side in a plane. Disposed between the hermetic vessels 3, 4 and 5 are electrically insulating barriers 6 for maintaining a necessary insulating distance therebetween. Also, electrically insulating barriers 6 made of an insulating material are inserted between the vacuum valves 3 and 5 and the hermetic vessel 1 in order to make the switchgear small-sized.
However, in the vacuum circuit interrupter 2 having the vacuum valves 3 to 5 arranged as above described, since the vacuum valves 3 to 5 are arranged in parallel in a plane, even when efforts are exerted to minimize the vacuum circuit interrupter 2 by inserting the insulating barriers 6 between the vacuum valves 3 to 5 and the hermetic vessel 1 to increase the insulating distance, there was a limitation in decreasing the size, particularly the width dimension, of the vacuum circuit interrupters 2 and the switchgear containing the vacuum circuit interrupters 2.
Accordingly, the main object of the present invention is to provide a vacuum circuit interrupter free from the above problems of the conventional vacuum circuit interrupter.
Another object of the present invention is to provide a vacuum circuit interrupter having a small width dimension and suitable for use in a compact switchgear.
With the above objects in view, the present invention resides in a vacuum circuit interrupter for use in a switchgear connectable to a three-phase ac power system and having for each phase a vacuum valve including a pair of separable electrodes supported within a hermetic vessel by an electrode, characterized in that axes of the vacuum valves for three phases are arranged in parallel and at apexes of a triangle.
The vacuum circuit interrupter may further comprise an electrically insulating barrier for insulating said vacuum valve from another vacuum valve in another phase and from said hermetic vessel.
The vacuum valves may be supported by said insulating barrier.
The insulating barriers may be partially overlapped each other between the vacuum valve and the hermetic vessel.